E.P. Pappa1, M.E. Christopoulou , T.J. Mertzimekis , P ... · accessible location and (i) its vast...
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E.P. Pappa 1 , M.E. Christopoulou 2 , T.J. Mertzimekis 1 , P. Nomikou 2 , S. Carey 3 , P. Polymenakou 4 and D. Papanikolaou 2 1 Faculty of Physics, University of Athens, Zografou Campus, GR-15784, Athens, Greece 2 Faculty of Geology and Geoenviroment,University of Athens, Zografou Campus, GR-15784, Athens, Greece 3 University of Rhode Island, 215 S. Ferry Road, Narragansett, Rhode Island 02882, USA 4 Hellenic Centre for Marine Research, P.O.Box 2214, GR-71003, Heraklion, Greece The basics The submarine volcano Kolumbo is the largest one of a group of 20 volcanic cones (Kolumbo volcanic chain) about 7 km NE of Santorini island. During its first detailed exploration an active hydrothermal vent field (HVF) was discovered in 2006, offering hints and clues for a plethora of phenomena. Kolumbo’s almost isolated cone also presents an ideal research site due to its accessible location and (i) its vast variety of mineral geomorphology, fauna and habitats, (ii) its variety of related natural hazards (lava flows to tephra flows, pyroclastic flows, landslides, earthquakes, tsunamis) and (iii) being an extreme environment (vertical inner crater walls, high Temperature, low pH, unstructured natural obstacles). Figure 1: Vessels, ROVs and CTD sensor used during the expeditions. E/V Nautilus R/V AEGAEO ROV Argus ROV Hercules CTD probe Cruises • E/V Nautilus collected data from Kolumbo during three different expeditions, occurred on (i) August 2010 (NA007), (ii) October 2010 (NA011) and (iii) September 2011 (NA014). • The cruise SeaBiotech-2, conducted by R/V Aegaeo during September 2013, collecting data both over Santorini’s and Kolumbo’s hydrothermal vent fields. Conclusions • Detailed in situ CTD measurements provided indication for hydrothermal vent field activity in Kolumbo and Santorini’s caldera. • CTD anomalies over the HVF can be used reliably to trace activity • The CTD depth profiles in Kolumbo are directly correlated to the unique geomorphological setting of its crater Figure 2: Typical profiles of temperature, sound velocity, salinity and conductivity directly above Kolumbo’s active hydrothermal vent field (here is the case for 31.07.2010, 15:00-16:00). Intense anomalies are recorded signifying strong hydrothermal activity Figure 3: Comparison between Kolumbo’s (left column) and Caldera’s (right column) depth profiles of salinity (top row) and density (bottom row). Kolumbo’s hydrothermal vent field is clearly a lot more active. Analysis • Analysis was performed using standard open-source utilities (awk, bash, gnuplot etc) on Linux and Mac OSX. • Over 8,000 2D and 3D Depth profiles of physicochemical parameters were created. • Special focus was given to Salinity, Temperature, Density, Conductivity, Sound Velocity and Oxygen levels. • Detailed profiles, time series and comparison plots between Santorini and Kolumbo have also been examined thoroughly. Methodology • In both cruises, in-situ measurements were carried out with precalibrated CTD probes. • In the case of Nautilus, CTD data were collected by integrated CTD sensors on the ROVs and via a drop-down operation real-time data were provided. • Additionally, on Aegaeo, the CTD instrument was attached to a metal rosette. The rosette was lowered down to the seafloor sending real-time measurements to the research vessel through a conducting cable (vertical cast method). Kolumbo Caldera Figure 4: Synthetic topographic relief map of the northern area of Santorini volcanic field. Insets represent salinity-depth profiles above the vent fields. Results • Observed CTD anomalies in data from Kolumbo provided strong indication of hydrothermal activity (Fig. 2 & 4) • The HVF in Santorini’s caldera showed no activity during measurements in 2013 (Fig. 3 & 4) • There is strong correlation between Kolumbo’s crater geomorphology and the depth profiles of CTD parameters. The shallow, closed crated with high walls of high inclination is mostly responsible for the formation of four distinct zones, where CTD data behave differently: a high variation zone from surface to ~80 m, a zone where the turbid waters are responsible for small CTD anomalies down to ~230 m, a zone down to ~497 m where the closed cone presents very stable conditions and a very disturbed layer above the vents (Fig. 5) Acknowledgments Special thanks to R/V Aegaeo and E/V Nautilus crews for assistance in operations and data sampling. Figure 5: The depth profiles of CTD data are distributed over four different zones, depending on the geomorphological setting. This correlation is seen for the first time for a submarine volcano with an active HVF.
Transcript of E.P. Pappa1, M.E. Christopoulou , T.J. Mertzimekis , P ... · accessible location and (i) its vast...
E.P. Pappa1, M.E. Christopoulou2, T.J. Mertzimekis1, P. Nomikou2, S. Carey3, P. Polymenakou4 and D. Papanikolaou2
1 Faculty of Physics, University of Athens, Zografou Campus, GR-15784, Athens, Greece 2 Faculty of Geology and Geoenviroment,University of Athens, Zografou Campus, GR-15784, Athens, Greece
3 University of Rhode Island, 215 S. Ferry Road, Narragansett, Rhode Island 02882, USA 4Hellenic Centre for Marine Research, P.O.Box 2214, GR-71003, Heraklion, Greece
The basics
The submarine volcano Kolumbo is the largest one of a group of 20 volcanic cones (Kolumbo volcanic chain) about 7 km NE of Santorini island. During its first detailed exploration an active hydrothermal vent field (HVF) was discovered in 2006, offering hints and clues for a plethora of phenomena. Kolumbo’s almost isolated cone also presents an ideal research site due to its accessible location and (i) its vast variety of mineral geomorphology, fauna and habitats, (ii) its variety of related natural hazards (lava flows to tephra flows, pyroclastic flows, landslides, earthquakes, tsunamis) and (iii) being an extreme environment (vertical inner crater walls, high Temperature, low pH, unstructured natural obstacles).
Figure 1: Vessels, ROVs and CTD sensor used during the expeditions.
E/V Nautilus
R/V AEGAEO
ROV Argus
ROV Hercules
CTD probe
Cruises • E/V Nautilus collected data from Kolumbo during three different expeditions,
occurred on (i) August 2010 (NA007), (ii) October 2010 (NA011) and (iii) September 2011 (NA014).
• The cruise SeaBiotech-2, conducted by R/V Aegaeo during September 2013, collecting data both over Santorini’s and Kolumbo’s hydrothermal vent fields.
Conclusions • Detailed in situ CTD measurements provided indication for hydrothermal
vent field activity in Kolumbo and Santorini’s caldera. • CTD anomalies over the HVF can be used reliably to trace activity • The CTD depth profiles in Kolumbo are directly correlated to the unique
geomorphological setting of its crater
Figure 2: Typical profiles of temperature, sound velocity, salinity and conductivity directly above Kolumbo’s active hydrothermal vent field (here is the case for 31.07.2010, 15:00-16:00). Intense anomalies are recorded signifying strong hydrothermal activity
Figure 3: Comparison between Kolumbo’s (left column) and Caldera’s (right column) depth profiles of salinity (top row) and density (bottom row). Kolumbo’s hydrothermal vent field is clearly a lot more active.
Analysis • Analysis was performed using standard open-source utilities
(awk, bash, gnuplot etc) on Linux and Mac OSX. • Over 8,000 2D and 3D Depth profiles of physicochemical
parameters were created. • Special focus was given to Salinity, Temperature, Density,
Conductivity, Sound Velocity and Oxygen levels. • Detailed profiles, time series and comparison plots between
Santorini and Kolumbo have also been examined thoroughly.
Methodology • In both cruises, in-situ measurements were carried out with precalibrated
CTD probes. • In the case of Nautilus, CTD data were collected by integrated CTD sensors
on the ROVs and via a drop-down operation real-time data were provided. • Additionally, on Aegaeo, the CTD instrument was attached to a metal
rosette. The rosette was lowered down to the seafloor sending real-time measurements to the research vessel through a conducting cable (vertical cast method).
Kolumbo Caldera
Figure 4: Synthetic topographic relief map of the northern area of Santorini volcanic field. Insets represent salinity-depth profiles above the vent fields.
Results • Observed CTD anomalies in data from Kolumbo provided strong indication of
hydrothermal activity (Fig. 2 & 4) • The HVF in Santorini’s caldera showed no activity during measurements in
2013 (Fig. 3 & 4) • There is strong correlation between Kolumbo’s crater geomorphology and
the depth profiles of CTD parameters. The shallow, closed crated with high walls of high inclination is mostly responsible for the formation of four distinct zones, where CTD data behave differently: a high variation zone from surface to ~80 m, a zone where the turbid waters are responsible for small CTD anomalies down to ~230 m, a zone down to ~497 m where the closed cone presents very stable conditions and a very disturbed layer above the vents (Fig. 5)
Acknowledgments Special thanks to R/V Aegaeo and E/V Nautilus crews for assistance in operations and data sampling.
Figure 5: The depth profiles of CTD data are distributed over four different zones, depending on the geomorphological setting. This correlation is seen for the first time for a submarine volcano with an active HVF.
